This invention relates to a refuelling system which is particularly adaptable for use whilst refuelling aircraft, but could have applications in other areas, for example, in the refuelling of water and other land vehicles.
For ease of description, however, we shall describe the invention when applied to aircraft refuelling.
Aircraft refuelling is done in a number of different ways. For example, the fuel may be provided either from a hydrant system which is underground in the area of the airport where refuelling occurs, and in which the fuel is maintained under pressure, or from a tanker in which the fuel is carried and which has a self-contained pump to enable the fuel to be pumped from the tanker to the aircraft.
Depending on the aircraft type, refuelling can sometimes be done from the ground but, in some aircraft, it is necessary for the refueller to lift the refuelling hose and nozzle a substantial distance, often by using a mechanically raised work platform or steps.
It has been conventional in refuelling systems to provide the refueller with a deadman control handle device which necessitates an action by the refueller within certain prescribed time periods to ensure that refuelling continues, but, at the same time, to ensure that the refueller is aware and alert.
Conventionally, these devices have been connected to the refuelling apparatus by means of a cable or the like, but there have been proposed systems where the device is separate from the apparatus.
Generally in a refuelling operation, the refueller connects an earth to the aircraft before connecting the filling nozzle, to avoid any likelihood of sparks which might ignite the fuel.
As a matter of course, this earth cable is connected to the aircraft at all times whilst the nozzle is connected, that is, it is connected before the nozzle is connected and disconnected after the nozzle is disconnected.
This is normally done by a conductor which is connected back to the refuelling vehicle, but which may be associated with the filling hose.
It will be appreciated, particularly where high level refuelling is required, that there can be a substantial length of hose in use and this is normally held on a reel in the refueller's vehicle.
The normal practice is that, when refuelling is finished, the refueller carries the nozzle, which is relatively expensive, back to the vehicle and then initiates the spool rewind.
The hose is then rewound and, over a substantial part of its distance, is being brought back over itself until the final length of hose is taken up on the reel and the nozzle is either held on the reel or can be clipped or otherwise held to the vehicle.
Whilst, theoretically, this is the way in which the device is operated, practically, on many occasions, a refueller can simply leave a nozzle on the ground, walk back to his vehicle, and operate the rewind, with the consequent possible damage or, if not accidental damage, marking and otherwise detrimental effect on the nozzle itself.